Disclosed is a method of synthesizing a water-free nanotube capable of efficiently encapsulating a functional substance therein, in large quantities. The method comprises: dissolving, in an organic solvent heated up to a temperature equal to or less than a boiling point thereof, an N-glycoside type glycolipid represented by the following general formula (1): G-NHCO-R 1 (wherein G represents a sugar residue from which a hemiacetal hydroxyl group bonded to an anomeric carbon atom of the sugar is excluded and R 1 represents an unsaturated hydrocarbon group having 10 to 39 carbon atoms), or a peptide-lipid conjugate represented by one of the following general formulas (2) and (3): R 2 CO (NH-CHR 3 -CO) m OH and H (NH-CHR 3 -CO) m NHR 2 (wherein: R 2 represents a hydrocarbon group having 6 to 24 carbon atoms R 3 represents an amino-acid side chain and m represents an integer of 1 to 10) (i) slowly cooling the obtained solution, and maintaining the cooled solution undisturbed at room temperature, or (ii) concentrating the obtained solution, and maintaining the concentrated solution disturbed at room temperature, or (iii) adding to the obtained solution a poor solvent for the N-glycoside type glycolipid or the peptide-lipid conjugate, and maintaining the mixed solution undisturbed at room temperature collecting from the resulting solution a hollow fibrous organic nanotube formed through self-assembling in the stationary solution, and drying the collected hollow fibrous organic nanotube, in air at room temperature or by heating under reduced-pressure, to obtain a hollow fibrous organic nanotube.
